CMS COLD BOX – CLEANING
RISK ANALYSIS
04 December 2015
EDMS
Prepared by:
Prepared by
Checked by
Approved by
Laetitia Bardo PH-CMX
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TABLE OF CONTENT
1
SCOPE AND OBJECTIVES ............................................................................... 3
2
CLEANING PROCESS DESCRIPTION ................................................................... 3
2.1
Description .................................................................................................................................. 3
2.2
Location....................................................................................................................................... 4
2.3
VERTREL XF Risks and Properties ................................................................................................ 5
3
SAFETY MEASUREMENTS CONTINUOUSLY IMPLEMENTED....................................... 9
4
SCENARIOS STUDY.................................................................................... 10
4.1
Solvent Machine Leak in USC55 –S3 (underground area) ........................................................ 11
4.2
Solvent Machine transport in PM54 lift .................................................................................... 12
4.3
Leak during the disconnection of the solvent machine from the cold Box .............................. 13
4.4
Small leak of a pipe/equipment during the running ................................................................. 14
4.5
Power cut .................................................................................................................................. 15
5
DOCUMENTATION .................................................................................... 16
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1
SCOPE AND OBJECTIVES
Due to a pollution of Breox oil identified in the CMS cold box, a cleaning process will be
performed during one month in the USC55 – CMS service cavern. The process is unusual. This
cleaning has never been drawn up in underground areas.
This document aims to analyse critical scenarios endangering people life and the environment
and which might occur during different phases of the cleaning process. The goal is to insure
that the risks are identified and controlled.
Critical Scenarios identified:
1
2
3
4
5
2
Solvent machine in USC55 in S3
Transport of solvent machine filled in in the PM54 lift
Leak during disconnection of the solvent machine from the cold box
Small leak from the pipes/equipment
Power cut (ventilation diesel)
CLEANING PROCESS DESCRIPTION
2.1 Description
The solvent machine which will be used has been built by an Italian company, MEG, according
to CERN requirements. The solvent machine consists of 2 stainless-steel tanks of 1 m3 each,
1 purifier, 2 pumps, … A retention tank of 344L is installed under both tanks and the purifier.
All retentions are connected to each other. The tanks containing the solvent are equipped
with a high level sensor which stops the machine when activated.
Total weight of the machine empty: 1 000 kg
One tank weight:
Purifier weight:
Solvent Machine dimensions: Depth m x width m x height 1.50 m
One tank dimension:
Purifier dimension:
Volume of solvent inside a tank: 1 m3 => 1600 kg
The command of the solvent machine are executed via a touch screen, plus an emergency
button is installed to stop the machine in case of emergency.
The condenser, mixed water chiller and dry vacuum pump will be provided by CERN EN-CV.
Total weight of the condenser empty: ??? kg
Volume of solvent which might be inside:
Where is located the exhaust of the cold box vent?
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Figure 1 : Cleaning PDF – Extracted from CMS cryogenics review TE-CRG/C-Fabre
Cleaning process
Drying process
Distillation 48-55°C depending on the product. Nitrogen exhaust at the surface.
2.2 Location
The solvent machine will be located in USC55 in level-2 S3.
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2.3 VERTREL XF Risks and Properties
Extract from MSDS
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Expansion: 1m3 of liquid solvent = 120 m3 gaseous phase
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3
SAFETY MEASUREMENTS CONTINUOUSLY IMPLEMENTED
Technical
- Adapt the ventilation


Cavern Volume = 2000 m3 air.
Only fresh air pulsed : Flow rate= 10 000 m3/hour – (the air is warmed up)
+ “Brassage” = 30 000 m3/hour pulsing
= 40 000 m3/hour pulsing
 Natural extraction through the pit
 Air renewed every 12 minutes – 5 renewal/hour



-
In case of emergency: Extraction (“désenfumage”) 20 000 m3/hour – test will be
drawn up by Frederic Juban and he will also explanation on how to activate the
system to CMS collaborators (To be completed: 16 5000, Antonio, Maf, Sandro,) ->
to be planned
Install aerolic connection on the “ desenfumage” system to collect the vapours at the
source -> to be done by EN-CV
If some areas seems not to be properly ventilated, extractors can be added –>
extractors are ordered
Portable ODH always worn by personnel intervening in USC55 and UXC55 -> the ODH
detector triggered in presence of VERTREL XF
Move one of the two ODH sensors located under the cold box
Retention tank under the condenser -> check if the CMS retention tank are big enough
Retention tank included in the solvent machine -> retention is >1m3 once the machine
installed
CO2 Fire extinguishers -> check that a sufficient amount of fire extinguisher are present
on site.
Obstructing plate -> Ordered
Absorption kit already in USC55 level -2 S3 -> check if it is compatible with the product
used
Mobile shower -> to be ordered? + Retention for rinsing water
Rinse eye already in USC55 level -2 S3 inside the absorption kit -> keep the absorption
cabinet open
Organisational
-
Fire brigade will be informed about the intervention and the risks present (provide the
product MSDS) -> organise a visit
Access limited -> put barriers level-1 and level-2 with panel indicating the reason,
duration, contact person
Check if shifters will be present during nights and weekends. If no check with the Fire
Brigade if they can patrol the area.
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Documentation
-
MSDS close to the tank
Tank identified with the name of the product and risk pictograms
Instruction what to do in case of spill -> to be adapted
Instruction what to do in case of projection -> already existing
Training
-
All persons intervening have followed the appropriate safety trainings and have the
access to work in the USC55 cavern -> email sent
Foreseen a specific training on site to get people -> organise a Safety briefing for people
intervening to get familiar with the premises and safety equipment and procedure
Chemical awareness on SIR online will be followed by all people intervening
List among the people intervening which one are First-aider -> list of people intervening
List among the people intervening which one followed the fire extinguisher training
courses -> list of people intervening
At least 1 chemist will always be on site during working hours
-
Additional safety measures will be implemented according to the scenario.
4
SCENARIOS STUDY
Legend
Csq:
Cau:
Consequence
Cause
Preventive/Protective actions
State
Decision
Critical situation
Remaining questions
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4.1 Solvent Machine Leak in USC55 –S3 (underground area)
1 - Solvent machine leak
Cau: Level High
Cau: Manufacturing default
Cau: Co-activity and transit LHC tunnel/CV room
Damage of the machine while moving some objects
Csq: Projection of VERTREL
SION or XF on people
Csq: Spill of VERTREL XF – 1 m3
People injured
No
Leak
detected?
Yes
Cau: Liquid observed in the retention
Caus: No body is in the area
Csq: ODH Hazard in level -2 S3
Csq: Retention tank full
Chemical in the retention
Floor quality? Dispersion at level -3?
ODH detectors?
Yes
No
Floor/Air/Water pollution
Personnel exposed to ODH
ODH alarm

Level -2/Level -3 is it tight?
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4.2 Solvent Machine transport in PM54 lift
Solvent Machine transport in PM54 Lift
No
Yes
Lift Failure?
Cau: Technical problem
Csq: 1 m3 of chemical product stucked in the lift
No
Machine Leak?
Yes
Yes
Machine Leak?
No
How do we detect the leak?
Cau: damaged during the transport
Cau: system not properly closed
Csq: 1 m3 of chemical product spill in the PM54 pit
Csq: Chemical vapours pushed in USC55 service cavern
Csq: Exposure of personnel
Csq: ODH
Lift technicians intervention
Solvent Machine leaking in the lift
Solvent machines in S3




Acceptance weight inside the lift: 3000 kg
Lift dimensions: Depth 2.70 m x width 1.85 m x height 2.70 m
Number of lift travels needed: 3, but only two with big quantities of solvent
The tank hooks for the transport cannot be used if the machine is full. Transport possible with Forklift?
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4.3 Leak during the disconnection of the solvent machine from the cold Box
Leak during disconnection solvent machine/Cold Box
Cau: Product not expected still in the pipe
Csq: Spill of 10/20L of chemical product in
the level -1 and -2 on the floor and electrical
equipment located in -2.
Floor/Water pollution
Power cut, short
circuit
Csq: exposition of
personnel
Diziness
Csq: Projection of chemical
product on people
Depends on the product
Skin Irritation/ Eye Burn
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4.4 Small leak of a pipe/equipment during the running
Stainless-steel pipes’ small leak
Condenser’s leak
Cau: Technical problem
Cau: damaged during the operation
Cau: Connection not tight
Cau: Technical problem
Cau: damaged during the operation
How to fix the leak? Who shall be contacted?
Csq: Continuous small release creating an
accumulation of chemical product in some
areas => ODH
Oxygen deficiency

Csq: Exposition of
personnel
Diziness
Csq: Spill of “volume” of chemical product in
chemical product in the level -1 and -2 on the
floor and electrical equipment located in -2.
Power cut, short
circuit
Floor/Water/Air pollution
Water and floor pollution not taken into consideration for the case of pipes’ leak because the quantities
are very small and the solvent will evaporate
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4.5 Power cut
Power cut
Cau: Someone push on an AUG
Cau: Incident in the area cutting the power
Csq: Stop of the process
Solvent remaining in the lines
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5
DOCUMENTATION
[1]
MSDS VERTREL XF
[2]
INSTRUCTION_Projection Produit chimique, (FR)
[3]
Stockage des produits chimiques – Test du bac de rétention au point 5 – EDMS 1252049
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